Stack- and Queue-like Dynamics in Recurrent Neural Networks

What dynamics do simple recurrent networks (SRNs) develop to represent stack-like and queue-like memories? SRNs have been widely used as models in cognitive science. However, they are interesting in their own right as non-symbolic computing devices from the viewpoints of analogue computing and dynamical systems theory. In this paper, SRNs are trained oil two prototypical formal languages with recursive structures that need stack-like or queue-like memories for processing, respectively. The evolved dynamics are analysed, then interpreted in terms of simple dynamical systems, and the different ease with which SRNs aquire them is related to the properties of these simple dynamical Within the dynamical systems framework, it is concluded that the stack-like language is simpler than the queue-like language, without making use of arguments from symbolic computation theory

Working Paper 40 - Industrial Restructuring in Africa During the1990s: Outcomes and Prospects

Since the advent of political independence, many governments in Africa have looked to themanufacturing sector as the main vehicle of structural transformation and reduction of dependenceon primary exports. However, it is now generally accepted that “misguided attempts to promoteindustrialisation without regard to comparative advantage or stage of development have led toinefficient use of resources in many countries” (World Bank, 1992:122). During the 1970s, almostone-third of African countries had negative average annual rates of manufacturing output growthand, in another quarter, these growth rates stagnated at below 2.5 percent. An important objective of the economic reform programmes that are currently being pursuedin almost all African countries is to eliminate the “inefficient use of resources” by industrial enterprises.It is clear that the industrial sector in most African countries is being profoundly affected by thisprocess of reform which has accelerated markedly during the 1990s. However, there has beenremarkably little independent analysis of just how successful industrial restructuring in Africa hasbeen. Two reviews of structural adjustment programmes undertaken by the World Bank in 1992and 1994 concluded that industrial restructuring had been successful in the majority of countriesunder scrutiny and that this was particularly so among those countries that had most consistentlypursued comprehensive macroeconomic reforms (see World Bank, 1992a and 1994). But othereconomists outside of the World Bank have been less sanguine and some have argued that “structuraladjustment programmes damage the prospects for industrialisation” (Stoneman, 1994:104) andmay, in fact, be leading to wholesale de-industrialisation.The purpose of this paper is to review the industrial performance of African economies duringthe 1990s and to then discuss the principal reasons why this performance, particularly with respectto the manufacturing sector, continues to be so poor in the majority of countries. The discussion willbe structured as follows. Section 1 outlines the broad objectives of industrial restructuring as thesehave been interpreted by the World Bank. Section 2 addresses the weaknesses of the main datasources that are generally relied upon in assessing the industrial sector. Section 3 reviews theperformance of the industrial sector, looking specifically at the following indicators: output growth,share of GDP, the sectoral composition of output, private and foreign investment, exports, andemployment and training. Section 4 then analyses the principal factors that have affected theperformance of the industrial sector, focusing in particular on investment, exports, and productivity.Finally, in Section 5, the prospects for the industrial sector and the role of government policy arebriefly considered.

Levels and Variations of Violation in Rape.

This chapter investigates the variations in crime scene behaviour revealed in a sample of victim statements in cases of stranger sexual assault. Building on previous findings by Canter and Heritage (1990), and Canter (1994), it was hypothesised that there existed a scale of differing levels of violation by the offender. This scale, based upon actions in the offence, ranged from personal violation, through to physical violation and finally, at the most extreme level, sexual violation. Offences could also be differentiated at the personal and physical levels in terms of hostile, controlling, stealing or involving thematic emphases to the criminal’s actions. To test these hypotheses, crime scene data from the first detected offences of 112 British rapists were analysed using a multi-dimensional scaling procedure to explore the relationships amongst crime scene actions. The results provided empirical support for the four action themes as different expressions of various intensities of violation. The implications that these findings have for the investigation of stranger sexual assault and treatment of victims are discussed

The Impact of HIV/AIDS on the University of Botswana: Developing a Comprehensive Strategic Response

Health Economics and Policy,

Mining whole sample mass spectrometry proteomics data for biomarkers: an overview

In this paper we aim to provide a concise overview of designing and conducting an MS proteomics experiment in such a way as to allow statistical analysis that may lead to the discovery of novel biomarkers. We provide a summary of the various stages that make up such an experiment, highlighting the need for experimental goals to be decided upon in advance. We discuss issues in experimental design at the sample collection stage, and good practise for standardising protocols within the proteomics laboratory. We then describe approaches to the data mining stage of the experiment, including the processing steps that transform a raw mass spectrum into a useable form. We propose a permutation-based procedure for determining the significance of reported error rates. Finally, because of its general advantages in speed and cost, we suggest that MS proteomics may be a good candidate for an early primary screening approach to disease diagnosis, identifying areas of risk and making referrals for more specific tests without necessarily making a diagnosis in its own right. Our discussion is illustrated with examples drawn from experiments on bovine blood serum conducted in the Centre for Proteomic Research (CPR) at Southampton University

Computerized crime linkage systems: A critical review and research agenda

Computerized crime linkage systems are meant to assist the police in determining whether crimes have been committed by the same offender. In this article, the authors assess these systems critically and identify four assumptions that affect the effectiveness of these systems. These assumptions are that (a) data in the systems can be coded reliably, (b) data in the systems are accurate, (c) violent serial offenders exhibit consistent but distinctive patterns of behavior, and (d) analysts have the ability to use the data in the systems to link crimes accurately. The authors argue that there is no compelling empirical support for any of the four assumptions, and they outline a research agenda for testing each assumption. Until evidence supporting these assumptions becomes available, the value of linkage systems will remain open to debate

A measure of non-convexity in the plane and the Minkowski sum

In this paper a measure of non-convexity for a simple polygonal region in the plane is introduced. It is proved that for "not far from convex" regions this measure does not decrease under the Minkowski sum operation, and guarantees that the Minkowski sum has no "holes".Comment: 5 figures; Discrete and Computational Geometry, 201

Geographic profiling survey:a preliminary examination of geographic profilers’ views and experiences

Geographic profiling (GP) is an investigative technique that involves predicting a serial offender’s home location (or some other anchor point) based on where he or she committed a crime. Although the use of GP in police investigations appears to be on the rise, little is known about the procedure and how it is used. To examine these issues, a survey was distributed internationally to police professionals who have contributed GP advice to police investigations. The survey consisted of questions designed to assess: (a) how geographic profiles are constructed, (b) the perceived usefulness and accuracy of GP, (c) whether core GP conditions are examined before profiles are constructed, and (d) the types of cases in which GP is used. The results suggest that geographic profiles are commonly used in operational settings for a wide range of crime types. This appears to be true even when GP conditions are violated. In addition, general perceptions of GP accuracy and usefulness appear to be high, but this is particularly true for respondents who use computerized GP systems (compared with spatial distribution strategies, such as centroids, or educated guesses). Computerized GP systems are also the most commonly used GP approach among our respondents, especially for those who have received formal training in GP. Although preliminary in nature, the results from this study help enhance understanding of how GP is used in police investigations around the world, and under what conditions. The survey also provides directions for future research